vb2008通过使用文本框的列表框搜索

Question

嗨我有一个窗体，找到，或者我应该说过滤器，使用文本框的列表框中的项目。我有一个文本框用于搜索和填充数据库项目的列表框。现在，列表框项目包括苹果，香蕉，浆果，腰果，柠檬，芒果，花生。如果我在文本框中输入'b'，列表框只显示香蕉和浆果。如果我键入'ba'，那么列表框只显示香蕉，但如果我输入'be'，那么它会显示浆果等等。我已经得到了这个工作（将代码标记为txtSearch事件中的注释）。我的问题是，如何在用户点击退格时将列表框中的项目返回给用户？因为现在我在列表框中有香蕉和浆果，当我删除在文本框中键入的文本时，它应该再次列出所有项目，以便如果我想搜索另一个项目，它将被再次过滤。提前致谢。

代码更新

Public Class Glossary 

Private Sub Glossary_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 
    Call List() 
    Refreshlist() 
End Sub 
Private Sub List() 
    Dim myCmd As New MySqlCommand 
    Dim myReader As MySqlDataReader 
    Dim myAdptr As New MySqlDataAdapter 
    Dim myDataTable As New DataTable 
    Call Connect() 
    With Me 
     STRSQL = "Select word from glossary" 
     Try 
      myCmd.Connection = myConn 
      myCmd.CommandText = STRSQL 
      myReader = myCmd.ExecuteReader 
      If (myReader.Read()) Then 
       myReader.Close() 
       myAdptr.SelectCommand = myCmd 
       myAdptr.Fill(myDataTable) 
       lstword.DisplayMember = "word" 
       lstword.ValueMember = "word" 
       If myDataTable.Rows.Count > 0 Then 
        For i As Integer = 0 To myDataTable.Rows.Count - 1 
         lstword.Items.Add(myDataTable.Rows(i)("word")) 
        Next 
       End If 
      End If 
      'lstword.Items.Clear() 
      'lstword.Items.AddRange(word.Where(Function(word) word.ToString().Contains(txtSearch.Text)).ToArray()) 
     Catch ex As Exception 
      MessageBox.Show(ex.Message) 
     End Try 
     myReader = Nothing 
     myCmd = Nothing 
     myConn.Close() 
     Call Disconnect() 
    End With 
End Sub 

Dim word As List(Of Object) 
Private Sub Refreshlist() 
    lstword.Items.Clear() 
    lstword.Items.AddRange(word.Where(Function(word) word.ToString().Contains(txtSearch.Text)).ToArray()) 
End Sub 
Private Sub txtSearch_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtSearch.TextChanged 
    lstword.Items.Clear() 
    lstword.Items.AddRange(word.Where(Function(word) word.ToString().Contains(txtSearch.Text)).ToArray()) 
    Refreshlist() 
    'Call List() 
    'lstword.BeginUpdate() 

    'Try 
    ' ' keep track of the "non-searched items" ' 
    ' Dim word As New List(Of Object) 

    ' lstword.SelectedIndices.Clear() 
    ' If txtSearch.Text.Length > 0 Then 
    '  For index As Integer = 0 To lstword.Items.Count - 1 
    '   Dim item As String = lstword.Items(index).ToString() 

    '   If item.IndexOf(txtSearch.Text, StringComparison.CurrentCultureIgnoreCase) >= 0 Then 
    '    lstword.SelectedIndices.Add(index) 
    '   Else 
    '    ' this item was not searched for; we will remove it ' 
    '    word.Add(index) 
    '   End If 
    '  Next 

    '  ' go backwards to avoid problems with indices being shifted ' 
    '  For i As Integer = word.Count - 1 To 0 Step -1 
    '   Dim indexToRemove As Integer = word(i) 
    '   lstword.Items.RemoveAt(indexToRemove) 
    '  Next 
    ' End If 
    'Finally 
    ' lstword.EndUpdate() 
    'End Try 

End Sub 
End Class 

Answer 1

第一步是将项目存储在屏幕外的内存中。例如：

lstword.Items.Clear() 
lstword.Items.AddRange(
    words.FindAll(
     Function(word) Return word.ToString().Contains(txtSearch.Text) 
     ).ToArray() 
    ) 

或者，使用LINQ：

Dim words As List(Of Object) 

然后，当你刷新列表框，只有与在内存中的列表匹配当前的标准该项目填充它

lstword.Items.Clear() 
lstword.Items.AddRange(
    words.Where(
     Function(word) word.ToString().Contains(txtSearch.Text) 
     ).ToArray() 
    ) 

UPDATE

由于英语新是具有EEM无法得到它的工作，这是很难说没有实际看到它有什么错你的代码，这里有一个完整的工作示例：

Public Class Form1 
    Dim words As New List(Of Object)(New String() {"apple", "banana", "berry", "cashew", "lemon", "mango", "peanut"}) 

    Private Sub RefreshList() 
     lstword.Items.Clear() 
     lstword.Items.AddRange(
      words.Where(
       Function(word) word.ToString().Contains(txtSearch.Text) 
       ).ToArray() 
      ) 
    End Sub 

    Private Sub txtSearch_TextChanged(sender As Object, e As EventArgs) Handles txtSearch.TextChanged 
     RefreshList() 
    End Sub 

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles Me.Load 
     RefreshList() 
    End Sub 
End Class 

更新2

我试着用你的代码与我推荐的建议，它工作得很好。这是为我工作的代码。试试吧，让我知道，如果它不为你工作：

Public Class Glossary 
    Private Sub Glossary_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 
     List() 
     Refreshlist() 
    End Sub 

    Private Sub List() 
     word.AddRange(New String() {"apple", "banana", "berry", "cashew", "lemon", "mango", "peanut"}) 
    End Sub 

    Private word As New List(Of Object)() 

    Private Sub Refreshlist() 
     lstword.Items.Clear() 
     lstword.Items.AddRange(word.Where(Function(word) word.ToString().Contains(txtSearch.Text)).ToArray()) 
    End Sub 

    Private Sub txtSearch_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtSearch.TextChanged 
     Refreshlist() 
    End Sub 
End Class 

如果这样的作品，那么所有你需要做的是改变List方法来从数据库中加载的而不是硬编码的列表。

Answer 2

让您的初始列表关闭数据库，在列表类e.g列表弹出它。 使用您的搜索文本来选择所有匹配的项目，并将它们放入列表框中。空白搜索文本，你只是把他们所有英寸

你也许想看看Foreach和List.FindAll以及。